Spectacle Lens Device Comprising an Electrically Adaptive Area, Spectacles, Use and Method For Operating Said Spectacle Lens Device

ABSTRACT

The invention relates to a spectacle lens device comprising at least one electrically adaptive area, wherein optical properties of the spectacle lens device can be controlled in an electric manner. The spectacle lens device is configured in such a manner that the optical properties of a predetermined or predeterminable control area can be controlled in an electrical manner which is essentially independent from the optical properties in a surrounding area. The invention also relates to the control area and to the surrounding area, respectively, about a partial area of the electrically adaptive area. The control area and the surrounding area do not a common area. The invention further relates to a pair of spectacles comprising a spectacle lens device, to the use of the inventive spectacle lens device and also to a method for operating an electrically adaptive area.

The present invention relates to a spectacle lens device, spectacles,the use of at least one spectacle lens device and a method for operatingan electrically adaptive area of at least one spectacle lens.

Spectacle lenses comprising electrically adaptive elements exist in thestate of the art. An electrically adaptive element may be, for example,a thin liquid crystalline film, which is mounted on a surface, forexample, the eye-sided surface of a spectacle lens. By applying anelectric voltage to the liquid crystalline film, the refractive index ofthe liquid crystalline film may be changed and controlled. If, forexample, the liquid crystalline film is disposed on the eye-sidedsurface of a spectacle lens, whereupon the liquid crystalline filmcovers in essence the entire surface facing the eye, the refractiveindex of the whole eye-sided surface of the spectacle lens may bechanged. If, in contrast, the liquid crystalline film is disposed onjust a subarea of the eye-sided surface of the spectacle lens, theresult is a change in the index of refraction of the liquid crystallinefilm [in a change in the index of refraction] in the subarea of theeye-sided surface of the spectacle lens, on which the liquid crystallinefilm is disposed.

However, the prior art devices enable only small variations in therefractive index, a feature that does not make it possible, for example,to achieve the necessary refractive indices for presbyopia. In order toachieve greater variations in the refractive index, one can, forexample, increase the thickness of the liquid crystalline layer.However, this approach has a negative impact on the optical phenomenonand, in particular, the translucency of spectacles and, in addition,necessitates the use of high electric voltages for scattering thevariations in the index of refraction of the liquid crystalline layer.Furthermore, thick liquid crystalline layers exhibit very slow reactiontimes.

As an alternative, for example, the state of the art teaches that liquidcrystals may be combined with Fresnel lenses in order to reduce thethickness of the liquid crystal layers. However, disturbing edgeartifacts between the neighboring effective edges reduce the imagequality.

Therefore, the object of the invention is to provide a spectacle lensdevice comprising an electrically adaptive element with improved opticalperformances. Furthermore, it is the object of the present invention toprovide suitable spectacles as well as a use for the correspondingspectacle lens device and a method for operating an electricallyadaptive area.

These problems are solved by means of the spectacle lens device, asclaimed in claim 1; the spectacles, as claimed in claim 15; the use ofat least one spectacle lens device, as claimed in claim 16, as well asthe method for operating an electrically adaptive area, as claimed inclaim 17. Preferred designs are the subject matter of the dependentclaims.

The present invention comprises a spectacle lens device comprising atleast one electrically adaptive area, wherein the optical properties ofthe spectacle lens device can be electrically controlled, whereby

-   -   the spectacle lens device is configured in such a manner that        the optical properties in a predetermined or predeterminable        control area can be electrically controlled in essence        independently of the optical properties in a surrounding area;    -   the control area and the surrounding area are subareas of the        electrically adaptive area; and    -   the control area and the surrounding area do not exhibit any        common areas.

Therefore, the electrically adaptive area comprises two separate areas,the control area and the surrounding area. The surrounding area is inessence the electrically adaptive area without the control area.Preferably the inventive spectacle lens device is configured in such amanner that a subarea of the electrically adaptive area, which is calledthe control area, can be selected for the purpose of an electricactuation. The electric actuation may be carried out by means of anelectric current and/or electric voltage, in order to control theoptical properties of the control area. In particular, the opticalproperties of the surrounding area, i.e., the remaining electricallyadaptive area, are essentially independent of the change in the opticalproperties in the control area.

Therefore, it is not the optical properties, such as the opticalrefractive index, of the whole electrically adaptive area, but only theoptical properties of the control area that are controlled by means ofthe spectacle lens device, according to the present invention.Consequently, a maximum change in the index of refraction may beachieved in the control area, i.e., in a subarea of the electricallyadaptive area. In conventional devices this change is achieved only overthe entire electrically adaptive area. Therefore, in contrast to theprior art, a comparable change in the index of refraction may beachieved in an advantageous manner over a smaller surface, i.e., thesurface of the control area. Hence, a larger optical effect (refractingpower) can be produced in the control area, as compared to the opticaleffect in conventional devices, which distribute the maximum change inthe index of refraction or the available refractive index variation overthe whole electrically adaptive area.

Preferably the electrically adaptive area may exhibit a thin liquidcrystalline layer. By applying an electric voltage, one can change therefractive index of the liquid crystal. At the same time the change inthe index of refraction is limited due to the properties of the materialof the liquid crystal and/or due to the voltage that is applied.Consequently with a predetermined electric voltage, which is applied tothe electrically adaptive area, a defined increase in the effect can beachieved over the area of the electrically adaptive element. If,however, the same voltage is applied to a preferably small subarea ofthe electrically adaptive area, the control area, one can achieve thesame increase in the index of refraction over a smaller threedimensional elongation, thus achieving a greater optical effect than ispossible, for example, over the whole electrically adaptive area.

Preferably the spectacle lens device also comprises, according to apreferred design of the present invention, a control unit. With the useof the control unit the predetermined or predeterminable control area ofthe electrically adaptive area can be specifically selected and/oractuated. In other words, with the use of the control unit an electricvoltage or rather an electric current can be applied in such a mannerthat the optical properties in the control area can be controlled. Inparticular, with the use of the control unit the position and/or thesize of the control area can be defined and/or controlled. Preferablywith the use of the control unit the optical properties of the controlarea can be controlled, for example, by varying the electric voltageand/or the electric current that is applied. At the same time theoptical properties of the surrounding area remain essentiallyunaffected.

Preferably the position, the size and/or the optical properties of thecontrol area can be changed and/or controlled in time. In this context,the concept “can be changed in time” means that the period, in which theposition, the size and/or the optical properties of the control area canbe changed and/or controlled, is in the microsecond to millisecondrange. In particular, the position, the size, and/or the opticalproperties of the control area can be quickly changed and/or controlledin such a manner that, for example, the position of the control area canbe adapted to the position of a visual point. In the context of theinvention the visual point is an intersecting point of a line of sightand/or the fixation line with the eye-sided surface of the spectaclelens device, according to the DIN EN ISO 13666:1998 definition. Withrespect to other technical terms reference is made to the pertinentstandards, in particular DIN EN ISO 13666:1998. Furthermore, withrespect to the technical terms that are used reference is made to HeinzDieps' and Ralf Bendowske's book Optik und Technik der Brille [Opticsand the Technology of Spectacles], published in 2002 by OptischeFachveröffentlichung GmbH, Heidelberg, and insofar as an integralcomponent of the invention is shown.

It is also possible for an optician to adjust the spectacle lens deviceto a spectacle wearer. Thus, for example, the optical properties of thespectacle lens device are adjusted to the values in the wearer'sprescription. When the visual acuity deteriorates, for example, over aperiod of months or years, an optician can compensate for thisdeterioration of the visual acuity by changing the optical properties ofthe spectacle lens device. In the context of the invention, “changeablein time” means in particular that over a period of months and/or yearsan optician will change, preferably at regular intervals, the opticalproperties of the spectacle lens device to the changed defects of theuser's vision.

Furthermore, it is possible for the optician to adjust just once thespectacle lens device to the requirements of the user of the spectaclelens device, thus, performing, for example, an irreversible process. Inparticular, the optical properties of the control area can bepermanently altered. For example, the spectacle lens device is made withpredetermined optical properties and, upon being sold, adjusted once bythe optician to match the values in the user's prescription, a featurethat also means changeable in time.

Preferably the electrically adaptive area is disposed on an eye-sidedsurface, on a lens-sided surface and/or between the surface facing theeye and the surface facing the lens. In an especially preferred designthe electrically adaptive area is configured substantially in the mannerof a plane.

Furthermore, the spectacle lens device comprises preferably an eyetracking device, which is configured to find an eye's line of sight bydetecting the position and/or movement of the eye. Hence, a visual pointmay be determined by means of the spectacle lens device or rather theeye tracking device. In this respect the visual point corresponds to anintersecting point of the line of sight and the eye-sided surface of theelectrically adaptive area. Preferably the position of the control areacan be controlled in such a manner that the control area comprises thevisual point. In an especially preferred design the geometric centerpoint of the control area is located in essence at the position of thevisual point.

The geometric center point of the control area is the point thatcorresponds to the control area's center of mass, with the exceptionthat the control area is substantially planar (that is, substantiallytwo dimensional); and the control area exhibits an essentially constantdensity. The vector GSP of the geometric center point can be calculatedusing the surface integral over the surface of the control area:

GSP = ∫_(surface) r ρ F,

where, in particular, p is a constant density by unit area of thecontrol area, where dF is a surface element, and r is a position vectorof the surface of the control area. Consequently the geometric centerpoint can be calculated analogous to the center of mass, where, insteadof a constant mass/volume/density, a constant mass/area/density is used,and a unit mass is assumed to be the mass of the control area.

Advantageously, in a preferred design of the spectacle lens device ofthe present invention, the user's gaze direction can be determined inessence at any time. In essence, the optical properties of the controlarea at essentially the visual point of the spectacle lens device areadapted in essence to the values of the user's prescription. Therefore,it is not necessary to adapt the optical properties of the entireelectrically adaptive area to the values of the user's prescription.Rather it is only necessary to adapt the optical properties to thevalues in the prescription in a small subarea of the electricallyadaptive area, the control area. Since the optical properties areadapted only in the control area, the adaptation of the opticalproperties is very flexible in an advantageous manner. For example, ahigh optical effect can be achieved due to the small surface of thecontrol area. The spectacle lens device is preferably configured in sucha manner that the position of the control area may be adjusted veryquickly to the visual point. Therefore, the optical properties of thecontrol area may be adapted in the period of time that the eye moves.Consequently the user does not perceive in essence the adaptation and/orcontrol of the optical properties. In particular, the user's perceptionwould be in essence the same if the optical properties were adapted overthe whole electrically adaptive area.

An inventive spectacle lens device permits the imaging errors of thewearer's eye to be corrected, thus producing a correction effect in thecontrol area. However, it is also possible for the spectacle lens deviceto exhibit defined optical properties, which are changed in the controlarea. For example, an already existing refractive index of the spectaclelens device can be increased in the control area. However, it is alsopossible, for example, to compensate in an advantageous way for theimaging errors in the spectacle lens of the spectacle lens device. Thus,for example, during the manufacturing process of the spectacle lensdevice and/or the spectacle lens of the spectacle lens device, largererror tolerances are permitted, since they can be compensated foressentially by the electronics in the control area.

Preferably the position, the size and/or the optical properties of thecontrol area can be regulated and/or controlled by means of at least oneelectrically conductive electrode. In an especially preferred design thespectacle lens device comprises a plurality of electrically conductiveelectrodes. The electrically conductive electrodes are disposedpreferably in and/or on the electrically adaptive area. Preferably theelectrically adaptive area does not completely cover the eye-sidedsurface and/or the lens-sided surface of the spectacle lens deviceand/or the spectacle lens of the spectacle lens device. However,preferably a plurality of electrically conductive electrodes arearranged at preferably regular intervals and cover in essence the entireeye-sided surface and/or a lens-sided surface of the spectacle lensdevice and/or the spectacle lens of the spectacle lens device.

Preferably the control area of the electrically adaptive area is inessence circular; in an especially preferred design the control areaexhibits an area ranging from 10 mm² to 100 mm², in particular rangingfrom about 35 mm² to 55 mm².

Preferably the control area ranges from about 0.2% to about 3.6%,especially preferred from about 0.7% to about 2.0% of the total area ofthe electrically adaptive area, in a standard spectacle lens thatexhibits a diameter ranging from about 60 mm to about 80 mm. The controlarea's share of the total area of the electrically adaptive areadecreases as the total area of the electrically adaptive area increases.

Preferably the size of the control area is chosen in such a manner thatthe control area comprises in essence an area and/or a surface of thespectacle lens device or rather the spectacle lens of the spectacle lensdevice that is pierced by the aperture ray path of the user's eye fordirect vision. For example, the aperture ray path exhibits anessentially conical shape.

Preferably the control unit is configured to control the control area insuch a manner that in a standardized operating position of the spectaclelens device a projection of the control area on the surface of thevertex sphere exhibits in essence an area ranging from about 10 mm² to100 mm², in particular ranging from 35 mm² to 55 mm², where the vertexsphere is a sphere, the center point of which coincides with the eye'spoint of rotation and the radius of which is equal to the distance ofthe eye's point of rotation from the vertex in a standardized operatingposition of the spectacle lens device.

A standardized operating position of the spectacle lens device is aposition, in which the distance between the eye's point of rotation andthe vertex of the spectacle lens is about 28.5 mm at a cornea vertexdistance of about 15 mm. The forward tilt of the spectacle lens orrather the spectacle lens device is about 8 deg.; the frame's angle ofinclination is about 0 deg. Furthermore, a standardized spectacle wearerwith a standardized pupil distance of about 63 mm is assumed.

Preferably the control area of the electrically adaptive area exhibitsdiffractive optical properties. For example, in the control area anamplitude grating can be produced dynamically by means of localstructures, which correspond to periodically alternating areas ofmaximum transmission and non-permeable grating points or rather gratingsurfaces. As an alternative, it is possible, for example, to produce alocally adaptive phase grating, in which a phase modulation of thetransmitted wave is achieved by means of a local change in the index ofrefraction so that structural interference in the first orderdiffraction maximum results in a diffractive deflection of the ray.Preferably the local diffractive structure comprises in essenceconcentric rings so that the essentially rotationally symmetricaldistribution of refractive power produces an essentially constanttransition to an inherent effect of the spectacle lens device.

In an especially preferred design the control area of the electricallyadaptive area exhibits in essence the properties of a gradient lens.Therefore, the index of refraction can increase or decrease radiallyoutwards preferably from the visual point and/or from the geometriccenter point, i.e., essentially the middle of the control area. Thus,the index of refraction is a function of the radial distance from thegeometric center point and/or center point of the control area.

Furthermore, the spectacle lens device comprises preferably a pluralityof electrically adaptive element cells. Therefore, the control area ofthe electrically adaptive area comprises at least one electricallyadaptive element cell, in an especially preferred design, a plurality ofelectrically adaptive element cells. For example, the electricallyadaptive area can comprise an essentially flat layer of a liquid crystalor rather can be made essentially of an essentially flat layer of aliquid crystal. For example, an electrode grating is arranged on theessentially flat liquid crystal. Then an element cell correspondsessentially to a three dimensional area of the liquid crystal, in whicha predetermined index of refraction can be achieved by apply an electricvoltage to the electrode grating. In particular, an electricallyadaptive element cell is the smallest unit of area that can be actuatedby the electrode grating (that is, the smallest unit of area, in which apredefined optical refractive index can be achieved).

As an alternative it is also possible to dispose only a small number ofelectrodes on and/or in the liquid crystal and to apply a voltage insuch a manner to the electrodes that an essentially continuousdistribution of the index of refraction of the liquid crystal isachieved in the control area.

As an alternative it is also possible for the electrically adaptive areato comprise a plurality of electrically adaptive element cells. Eachelectrically adaptive element cell forms in essence a defined unit. Eachof the electrically adaptive element cells may be, for example, anessentially independent electrowetting cell, i.e., a cell based on theso-called electrowetting principle. Hence, each of the electricallyadaptive element cells is supplied with voltage by means of anelectrode. Each of the electrically adaptive element cells, operating onthe electrowetting principle, comprises, for example, two essentiallytransparent liquids having different refractive indices and identicaldensities; yet one of the liquids is non-polar and the other is polar.By applying a voltage to the electrowetting cell a micro-lens can beproduced due to the form of the two immiscible liquids. The size of sucha cell, based on the electrowetting principle, can be equal in essenceto the size of the control area. However, it is also possible for thecontrol area to comprise a plurality of such lenses. Therefore, theoptical properties of the control area are changed by controlling and/orapplying the voltages to the cells, based on the electrowettingprinciple.

Preferably the electrically adaptive element cells are embedded in thespectacle lens device, in an especially preferred design, in thespectacle lens of the spectacle lens device.

Furthermore, the electrically adaptive element cells are disposed on asurface of the spectacle lens device, in an especially preferred design,in a surface of the spectacle lens of the spectacle lens device.

In an especially preferred design, the electrically adaptive elementcells are arranged in essence uniformly so that the spectacle lensdevice, especially preferred the spectacle lens of the spectacle lensdevice, is in essence totally covered by the electrically adaptiveelement cells. In other words, each visual point is located in anelectrically adaptive element cell, so that there is essentially no freespace between the element cells.

Furthermore, the present invention relates to spectacles with at leastone spectacle lens device, according to the present invention.

Furthermore, the present invention relates to the use of at least onespectacle lens device, according to the present invention, inspectacles. Hence, the optical properties of the control area of theelectrically adaptive area are adapted to the individual data of aspectacle wearer.

Preferably a position and/or a size of the control area can be adaptedto conform with a gaze direction, i.e., to conform with a visual pointof the user of the spectacle lens device. Therefore, in the controlarea, which comprises in essence the visual point, the opticalproperties of the spectacle lens device are adapted in essence to thevalues of the prescription of the spectacle wearer. Furthermore, theposition of the control area can be advantageously changed essentiallyin the period of time in which the visual point is changed by changingthe gaze direction. In other words, the position of the control areamoves in essence simultaneously with the position of the visual point.

Furthermore, the present invention relates to a method for operating atleast one electrically adaptive area of at least one inventive spectaclelens device, with the steps:

-   -   providing at least one spectacle lens device;    -   controlling the control area of at least one electrically        adaptive area in such a manner that the optical properties of        the control area match in essence the values in the prescription        of the spectacle wearer.

Preferably the optical properties of the control area of theelectrically adaptive area are adjusted, according to the inventivemethod, to match the individual data of a spectacle wearer.

Preferably the inventive method comprises the following additionalsteps:

-   -   detecting a line of sight by means of an eye tracking system;        -   determining a visual point, where the visual point is the            intersecting point of the line of sight with the eye-sided            surface of the electrically adaptive area;        -   positioning the control area in such a manner that the            control area comprises in essence the position of the visual            point.

The invention is described below by means of the attached drawings ofpreferred embodiments that serve merely as examples.

FIG. 1 is a frontal view of preferred spectacles, comprising a spectaclelens device, according to a preferred design of the present invention.

FIG. 2 is a frontal view of a spectacle lens device, according to FIG.1.

FIG. 3 depicts a preferred embodiment of the control area, according toFIG. 1.

FIG. 4 is a sectional view along line I-I from FIG. 1 of a preferreddesign of the present invention with a conventional curvature of thespectacle lens device.

FIG. 5 is a sectional view along line I-I from FIG. 1 of a preferreddesign of the present invention with a large curvature of the spectaclelens device.

FIG. 1 is a schematic drawing of a frontal view of preferred spectacles1, comprising a spectacle lens device 10, according to a preferreddesign of the present invention. The spectacle lens device 10 comprisesa conventional spectacle lens 12 with an electrically adaptive area 14.The electrically adaptive area 14 is produced, for example, by applyinga thin layer of a liquid crystal on an eye-sided surface 16 of thespectacle lens 12. Furthermore, the electrically adaptive area 14comprises an electrode grating, which consists of a plurality ofelectrodes 18. Furthermore, FIG. 1 depicts a control area 20. Thecontrol area 20 represents a subarea of the electrically adaptive area14. Hence, in this preferred design the control area 20 comprisespreferably nine electrically adaptive element cells 22. Furthermore,FIG. 1 depicts the geometric center point GSP of the control area 20that coincides in essence with a visual point DP. The remaining area ofthe electrically adaptive area 14 is the surrounding area 24.

Furthermore, the preferred spectacle lens device 10 comprises an eyetracking system 26, which is configured to detect a gaze direction ofthe eye (not illustrated) and to determine the visual point DP from thegaze direction. A control unit 28 is configured in essence to providefrom the plurality of electrically adaptive element cells 22 of theelectrically adaptive area 14 preferably those electrically adaptiveelement cells 22 with electric current or rather electric voltage thatare enveloped in essence by the control area 20. In the present designthe control area 20 comprises, for example, nine electrically adaptiveelement cells 22. The control unit 28 supplies in essence thoseelectrically adaptive element cells 22 with electrical voltage and/orelectric current from a battery 30 via the electrodes 18 that areessentially adjacent to the electrically adaptive element cell 22 thatcomprises the visual point DP. Preferably the electrically adaptiveelement cells 22 of the preferred design of the present inventionexhibit an essentially square cross section. Therefore, the control area20 also exhibits an essentially square cross section. Thus, theelectrically adaptive element cell 22 comprises the visual point DP inthe center of the control area 20.

FIG. 2 depicts the spectacle lens device 10 from FIG. 1, where theposition of the visual point DP has changed with respect to FIG. 1. Inconformity with the modified position of the visual point DP, theposition of the control area 20 was also modified. Again the controlarea 20 comprises nine electrically adaptive element cells 22, which areconfigured in the shape of a square. The central element cell 22, i.e.,the element cell 22, which is disposed in essence at the geometriccenter point GSP of the control area 20, comprises the visual point DP.The visual point DP and the geometric center point GSP of the controlarea 20 are essentially the same.

Preferably the control area 20 forms an electrically adaptive gradientlens. The index of refraction increases or decreases radially outwardsfrom the center, i.e., essentially from the geometric center point GSP.In this respect the index of refraction n is a function of the radialdistance r from the geometric center point GSP. For example, thisfunction can be chosen as follows.

${n(r)} = {\sum\limits_{l}\; {a_{i} \cdot r^{i}}}$

It is preferred that, if a₀ is approximately equal to the index ofrefraction of the spectacle lens 12 (i.e., a₀≈n_(G)), a₁ should be assmall as possible. Preferably |a₁|≦10 is true; and a₂ should move in thefollowing range,

${a_{2} \leq \frac{\left( {X + D} \right)}{d_{M}}},\mspace{14mu} {{where}\text{:}}$

n_(G)=the index of refraction of the spectacle lens 12,Z=the additional effect,d_(M)=the thickness of the liquid crystal layer, andD=the effect of the spectacle lens 12and where a₂ is usually negative.

The additional effect Z, for example, of a liquid crystal layer of thecontrol area 20 is generally calculated as an approximation according tothe equation:

${{Z \approx {D_{2\; Z} + \frac{D_{1\; Z}}{1 - {\frac{d_{M}}{a_{0}}D_{1\; Z}}} - \frac{2\; a_{2}d_{M}}{1 - {\frac{d_{M}}{a_{0}}D_{1\; Z}}}}} = {D_{2\; Z} + {D_{1\; Z}{Ne}} - {2\; a_{2}d_{M}{Ne}}}},{and}$

D₁Z=the refracting value of the front surface of the control area 20,D₂Z=the refracting value of the rear surface of the control area,d_(m)=the center thickness of the control area 20, andN_(e)=the self-enlargement of the control area 20.

If the control area 20 exhibits preferably a layer of liquid crystalhaving a layer thickness d_(m)≈20 μm and a diameter of about 4 mm; andif the maximum refractive index change is Δn≈0.25, then the result isapproximately an additional effect of Z≈2.5 dpt.

In order to produce the additional effect, a₀ need not coincide with therefractive index n_(G) of the spectacle lens 12, but rather can bechosen essentially at random. If the additional effect a₀ isapproximately equal to the refractive index n_(G) of the spectacle lens10, there are no disturbing flares, which can develop when thedifference between a₀ and the refractive index n_(G) of the spectaclelens 12 is large. Therefore, it holds preferably:

$a_{1} \approx {0\mspace{14mu} {and}\mspace{14mu} a_{2}} \approx {\frac{- z}{2 \cdot d_{M}}.}$

In particular, it holds preferably:

$a_{1} = {{0\mspace{14mu} {and}\mspace{14mu} a_{2}} = \frac{- Z}{2 \cdot d_{M}}}$

Advantageously it is also possible to correct the higher order imagingerrors. In conventional spectacle lenses this is only conditionallypossible, since each visual point must already exhibit a specificrefractive index for the gazing eye. Therefore, there are no degrees offreedom in order to correct, for example, coma and/or sphericalaberrations. With the present invention it is also advantageouslypossible to correct not only the defective vision of a spectacle wearerin essence at the visual site or rather at the visual point DP, but alsoto correct the optical errors of the spectacle lens 12 at the visualpoint DP and/or vary the optical properties of the spectacle lens 12 atthe visual point.

Imaging errors of higher order can be calculated, for example, by meansof the following processes.

-   -   Specify the gaze direction, the lens point and/or a point on the        front or rear surface of the spectacle lens. With the aid of        these points and the eye's point of rotation 36 (FIG. 4) a ray        path is clearly defined; and by calculating the rays a principal        ray HS (FIG. 4) can be calculated.    -   Calculate a position of an aperture stop by rotating an entrance        pupil of the eye 32 (FIG. 4) as a function of the gaze direction        and the eye's point of rotation 36 (FIG. 4). The center of the        aperture stop is located on the principal ray HS (FIG. 4).        Consequently the result is a new position of the aperture stop        for each gaze direction.    -   Calculate the aperture ray path SG (FIG. 4), by calculating the        rays, starting from an object (not illustrated) having varying        aperture angles.    -   Calculate a wavefront in the entrance pupil from the said rays        and the corresponding lengths of the optical paths.    -   Represent the wavefront by means of Zernike polynomials.    -   Calculate the imaging errors by means of the coefficients of the        Zernike polynomials, where the result is the astigmatism,        refractive index, coma and/or spherical aberrations, etc. for        each gaze direction.

In order to correct the higher order imaging errors, the coefficientsa_(i), where i>2, can be used. Both the higher order imaging errors thatare produced by the spectacle lens 12 and those imaging errors that theeye 32 itself exhibits can be corrected. In this way a vision of 2.0 orhigher can be produced in an advantageous way.

Furthermore, the refractive index profile, i.e., the refractive indexdistribution of the adaptive area, can be controlled as a function ofthe distance from the visual point DP and/or from the geometric centerpoint GSP in such a manner that the refractive index of the surroundingarea 24 is equivalent in essence to the refractive index of thespectacle lens 12, and there is an essentially sudden (i.e., notcontinuous) transition of the refractive index from the control area 20to the surrounding area 24. Consequently the effect and, thus, the imagethat is seen has a jump. This image jump exists in bifocal lenses and isnot a problem.

However, it is also possible for the refractive index transition fromthe control area 20 to the surrounding area 24 to run in an essentiallyconstant manner. Thus, there is advantageously no image jump.

Furthermore, a correction of the astigmatism can also be carried out, ifdesired, by the control area 20 of the electrically adaptive area 14.

Furthermore, the spectacle lens 12 may exhibit only simple spherical oraspherical surfaces; and imaging errors and/or visual acuity errors ofthe user of the spectacle lens 12 or rather the spectacle lens device 10can be carried out by means of the control area 20 of the electricallyadaptive area 14. The course of the gradient of the refractive index nlooks preferably as follows:

${n\left( {u,v} \right)} = {\sum\limits_{i,{j = 0}}^{n}\; {a_{ij}u^{i}v^{j}}}$

whereu=the distance from the visual point DP in the direction of a sphericaleffect.v=the distance from the visual point DP in the direction of anastigmatic effect.

Thus, the following approximation equations for the first expansionelements of the power series hold true in a manner analogous to theradial refractive index function, as described above:

a₁₀≈a₀₁≈0

and

${a_{0\; 2} \approx {\frac{Z_{sph} + Z_{cyl}}{2\; d_{M}}\mspace{14mu} {and}\mspace{14mu} a_{20}} \approx {{\frac{Z_{sph}}{2\; d_{M}}.\; {Preferably}}\mspace{14mu} {it}\mspace{14mu} {holds}\text{:}}}\mspace{11mu}$a₁₀ = a_(01 ) = 0  and$a_{02} \approx {{- \frac{Z_{sph} + Z_{cyl}}{2\; d_{M}}}\mspace{14mu} {and}\mspace{14mu} a_{20}} \approx {- {\frac{Z_{sph}}{2\; d_{M}}.}}$

Higher elements of the power series have in essence no effect on theoptical effect in the center of the control area 20 and can be used tocorrect the remaining imaging errors.

In order to produce an additional effect, a₀ and/or a₀₀ need notcoincide with the refractive index n_(G) of the spectacle lens 12, butrather can be chosen at random. However, if the difference of n_(G)−a₀is a large value, disturbing flares could ultimately develop.

Furthermore, the electrically adaptive element cells 22 need not exhibitan essentially square cross section. Rather it is possible for theelectrically adaptive element cells 22 to exhibit, for example, ahexagonal cross section, as shown in the schematic drawing in FIG. 3.The electrically adaptive area 14 comprises preferably a plurality ofelectrically adaptive element cells 22, which are arranged uniformly,i.e., essentially without any space between the individual electricallyadaptive element cells 22, in and/or on the electrically adaptive area14. In the control area 20 of the electrically adaptive area 14, only adefined number, for example, nineteen electrically adaptive elementcells 22 are supplied by the control unit 28 with electric voltage orrather electric current. Preferably eighteen electrically adaptiveelement cells 22 are arranged in essence symmetrically around a centralelectrically adaptive element cell 22. The central electrically adaptiveelement cell 22 comprises the visual point DP. Therefore, the controlarea 20 of the electrically adaptive area 14 exhibits an essentiallycircular cross section.

Instead of a liquid crystal film and an electrode grating, it is alsopossible for the electrically adaptive area 14 to exhibit a plurality ofelectrically adaptive element cells 22. Each electrically adaptiveelement cell 22 works on the electrowetting principle.

FIG. 4 is a sectional view of the preferred design of the spectacle lensdevice 10, according to FIG. 1, along the line I-I. Furthermore, FIG. 4shows, as a schematic drawing, an eye 32 with the aperture ray path SGdrawn in. The aperture ray path SG intersects the spectacle lens 12and/or the electrically adaptive area 14 in a visual area 34. The visualarea 34 conforms essentially with the control area 20. The visual pointDP coincides in essence with the geometric center point GSP of theelectrically adaptive area 14. Furthermore, FIG. 4 shows the surroundingarea 24 of the electrically adaptive area 14, which is in essence thearea of the electrically adaptive area 14, which is not comprised by thecontrol area 20.

When the aperture ray path SG is in essence the same and/or in essenceconstant, the surface of the control area 20 is a function of a radiusof curvature R of the eye-sided surface 16 of the spectacle lens 12.This is especially important for so-called sports spectacles, where, inparticular the rim region of the spectacle lens 12 may exhibit a smallerradius of curvature R, as shown, for example, in FIG. 5. Thus, thesurface of the visual area 34, compared to conventional spectacle lenses12, is reduced, as shown, for example, in FIG. 4. Consequently thecontrol area 20 of the electrically adaptive area 14 is also reduced,since the control area corresponds in essence to the visual area 34. Inparticular, the control area 20 is adapted in essence to the visual area34. Therefore, FIGS. 4 and 5 illustrate only the visual area 34, but notthe control area 20. The size of the control area 20 and, therefore,also the size of the visual area 34 correspond in essence to theinterface of the spectacle lens 12 with the essentially conical apertureray path SG.

LIST OF REFERENCE NUMERALS

-   1 spectacles-   10 spectacle lens device-   12 spectacle lens-   14 electrically adaptive area-   16 eye-sided surface-   18 electrode-   20 control area-   22 electrically adaptive element cell-   24 surrounding area-   26 eye tracking system-   28 control unit-   30 battery-   32 eye-   34 visual area-   36 point of rotation of the eye-   DP visual point-   GSP geometric center point-   SG aperture ray path-   HS principal ray-   R radius of curvature

1-19. (canceled)
 20. Spectacle lens device comprising at least oneelectrically adaptive area, for electrically controlling opticalproperties of the spectacle lens device, the spectacle lens device beingconfigured so that optical properties in a predetermined orpredeterminable control area are electrically controllable essentiallyindependently of optical properties in a surrounding area; wherein thecontrol area and the surrounding area are sub-areas of the electricallyadaptive area and do not have any common areas.
 21. Spectacle lensdevice, as claimed in claim 20, wherein position, size and/or theoptical properties of the control area are at least one of changeableand controllable time-wise.
 22. Spectacle lens device, as claimed inclaim 20, wherein the electrically adaptive area is disposed on at leastone of an eye-side surface, on a lens-side surface and between theeye-side surface and the lens-side surface of the spectacle lens device.23. Spectacle lens device, as claimed in claim 20, wherein theelectrically adaptive area is configured substantially in a planarmanner.
 24. Spectacle lens device, as claimed in claim 20, furthercomprising an eye tracking device, configured to find an eye's line ofsight by detecting eye position and/or movement, the eye tracking devicebeing configured to determine a visual point corresponding to anintersecting point of the line of sight with an eye-side surface of theelectrically adaptive area, and the position of the control area beingcontrollable so that the control area includes the visual point. 25.Spectacle lens device, as claimed in claim 24, wherein a geometriccenter point of the control area is located essentially at the positionof the visual point.
 26. Spectacle lens device, as claimed in claim 21,wherein at least one electrically conductive electrode is provided forcontrolling properties of the control area.
 27. Spectacle lens device,as claimed in claim 20, wherein a spectacle lens has a plurality ofelectrically conductive electrodes.
 28. Spectacle lens device, asclaimed in claim 20, wherein the control area has essentially an arearanging from about 10 mm² to 100 mm².
 29. Spectacle lens device asclaimed in claim 20, wherein the control areas has an area ranging fromabout 35 mm² to 55 mm².
 30. Spectacle lens device, as claimed in claim20, further comprising a control unit configured to control the controlarea so that in a standardized operating position of the spectacle lensdevice a projection of the control areas on a surface of the vertexsphere has essentially an area ranging from about 10 mm² to 100 mm²,where the vertex sphere is a sphere, a center point of which coincideswith an eye's point of rotation and a radius of which is equal to thedistance of the eye's point of rotation from the vertex in astandardized operating position of the spectacle lens device. 31.Spectacle lens device, as claimed in claim 30, wherein the range of thevertex sphere surface is from about 35 mm² to 55 mm².
 32. Spectacle lensdevice, as claimed in claim 20, wherein the control area has diffractiveproperties.
 33. Spectacle lens device, as claimed in claim 20,furthermore comprising a plurality of electrically adaptive elementcells, wherein the control area has at least one of the electricallyadaptive element cells.
 34. Spectacle lens device, as claimed in claim20, wherein the control area has a plurality of electrically adaptiveelement cells.
 35. Spectacles comprising at least one spectacle lensdevice as claimed in claim
 20. 36. Method of using at least onespectacle lens device as claimed in claim 20, in spectacles, comprisingadjusting optical properties of the control area to match a spectaclewearer's individual data.
 37. Method for operating an electricallyadaptive area of a spectacle lens device, as claimed in claim 20,comprising controlling with the spectacle lens device the control areaof the electrically adaptive element so that optical properties of thecontrol area essentially match predefined values in a spectacle wearer'sindividual data.
 38. Method, as claimed in claimed in claim 27, whereinthe optical properties of the control area are adjusted to match aspectacle wearer's individual data.
 39. Method, as claimed in claim 37,further comprising detecting a line of sight with an eye trackingsystem; determining a visual point that is an intersecting point of theline of sight with the eye-side surface of the electrically adaptivearea; and positioning the control area so that the control areaessentially comprises the position of the visual point.